Sökning: "Adaptive Optics"

Visar resultat 6 - 10 av 25 avhandlingar innehållade orden Adaptive Optics.

  1. 6. Extremely Large Telescopes Optical Design and Wavefront Correction

    Författare :Alexander Gontcharov; Astronomi - Genomgår omorganisation; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Astronomy; akustik; optik; Adaptive Optics; Extremely Large Telescopes; optical design methods; wavefront correction methods.; Electromagnetism; optics; Elektromagnetism; acoustics; space research; cosmic chemistry; Astronomi; rymdvetenskap; kosmisk kemi;

    Sammanfattning : An overview of the state of art within optical design of large astronomical telescopes is given. Recent advances within the field are presented. The importance of new computer-controlled mirror-polishing methods is emphasized. LÄS MER

  3. 7. Digital Dispersion Equalization and Carrier Phase Estimation in 112-Gbit/s Coherent Optical Fiber Transmission System

    Författare :Tianhua Xu; Sergei Popov; Gunnar Jacobsen; Jie Li; Magnus Karlsson; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Coherent transmission; chromatic dispersion; carrier phase estimation; digital signal processing; Optics; Optik; Photonics; Fotonik; SRA - ICT; SRA - Informations- och kommunikationsteknik;

    Sammanfattning : Coherent detection employing multilevel modulation format has become one of the most promising technologies for next generation high speed transmission system due to the high power and spectral efficiencies. With the powerful digital signal processing (DSP), coherent optical receivers allow the significant equalization of chromatic dispersion (CD), polarization mode dispersion (PMD), phase noise (PN) and nonlinear effects in the electrical domain. LÄS MER

  4. 8. Multi-Level Lossless Phase Modulation in Liquid Crystals for High-Speed Spatial Light Modulators

    Författare :David Engström; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; phase measurements; polarization; phase modulation; beam steering; Spatial light modulators; diffractive optics; ferroelectric liquid crystals;

    Sammanfattning : The spatial light modulator (SLM) is a compact device that enables highly precise control of light propagation with low drive voltages and no moving parts. By imposing a certain phase modulation onto the incident lightwave, functions such as multi-beam steering, beam shaping, and air turbulence corrections can be achieved in realtime. LÄS MER

  5. 9. Optimal Use of Peripheral Vision

    Författare :Karthikeyan Baskaran; Jörgen Gustafsson; Peter Unsbo; Staffan Carius; Michael Crossland; Linnéuniversitetet; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; off-axis refractive errors; peripheral aberrations; aberrometers; central visual field loss; preferred retinal locus; eccentric viewing; absolute central scotoma; adaptive optics; eccentric correction.; Optometry; Optometri;

    Sammanfattning : People who lose their central vision have to rely on their peripheral vision for all visual tasks. The ability to resolve fine details in the periphery is reduced due to retinal limitations and the optical aberrations arising from the use of off-axis vision. LÄS MER

  7. 10. A Stacked Prism Lens Concept for Next-Generation Hard X-Ray Telescopes

    Författare :Wujun Mi; Mats Danielsson; Peter Nillius; Ralf K. Heilmann; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; focusing X-ray telescopes; Wolter-I optics; stacked prism lens; focused UV lithography; grayscale e-beam lithography; proximity effect correction; angular resolution; effective collecting area; röntgenteleskop; Wolter-I-optik; staplade prismalinser; fokuserad UV-litografi; elektronstråle-litografi; Fysik; Physics;

    Sammanfattning : Over the past half century, the focusing X-ray telescope has played a very prominent role in X-ray astronomy at the frontier of fundamental physics. The finer angular resolution and increased effective area have enabled more and more exciting discoveries and detailed studies of the high-energy universe, including the cosmic X-ray background (CXB) radiation, black holes in active galactic nuclei (AGN), galaxy clusters, supernova remnants, and so on. LÄS MER